I have equal number of both. When I needed .260 Rem, there were no Redding in stock, so I got RCBS. When I needed dies for the 7 Rem Mag I got Redding Custom Competition. The 6.5 Creedmoor is Hornady dies. I also have a few Lee sets.

I like Hornady and Redding dies. I like the ease of the Hornady dies adjustments and the tear drop shaped expander ball. I like Redding for the die options. I order RCBS only when I have to. I HATE the screw driver and pliers or wrench needed to make the adjustments.

I like Redding over RCBS too, but when they're available, I actually prefer Forster's Benchrest Seater, so I own almost as many Forster die sets as Redding and RCBS. I have a few Hornady sets as well; they work fine except when you are seating a bullet over a compressed load of powder. Then the Hornady seater leaves an unsightly ring mark on the ogive of the bullet, at least IME.

And I have a Lee Collett die for most of the cartridges I load for. And of course, shoulder bump dies. And on and on....

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"For every complex problem there is an answer that is clear, simple.....and wrong." H. L. Mencken

I don't think I'm a precision skilled enough reloader to noticethe difference between Redding and RCBS in my final product. Ican imagine that having a Mic adjustment dial would be helpfulwhen loading multiple bullets for the same caliber. On caliberswhere I've settled into one bullet, maybe not as useful. RCBSalso makes higher-end dies with the Mic, but if I was looking in that price bracket, I'd likely go Redding just because.